mapnik/src/params.cpp

/*****************************************************************************
 *
 * This file is part of Mapnik (c++ mapping toolkit)
 *
 * Copyright (C) 2012 Artem Pavlenko
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 *****************************************************************************/

// mapnik
#include <mapnik/boolean.hpp>
#include <mapnik/params.hpp>
#include <mapnik/value_types.hpp>

// boost
#include <boost/variant/static_visitor.hpp>
#include <boost/variant/apply_visitor.hpp>
#include <boost/lexical_cast.hpp>
#include <boost/none.hpp>
#include <boost/optional.hpp>

namespace mapnik {

namespace params_detail {

template <typename T>
struct converter
{
    typedef boost::optional<T> return_type;
    static return_type extract(parameters const& params,
                               std::string const& name,
                               boost::optional<T> const& default_opt_value)
    {
        boost::optional<T> result(default_opt_value);
        parameters::const_iterator itr = params.find(name);
        if (itr != params.end())
        {
            boost::apply_visitor(value_extractor_visitor<T>(result),itr->second);
        }
        return result;
    }
};
} // end namespace params_detail

// parameters

parameters::parameters() {}

template <typename T>
boost::optional<T> parameters::get(std::string const& key) const
{
    return params_detail::converter<T>::extract(*this,key, boost::none);
}

template <typename T>
boost::optional<T> parameters::get(std::string const& key, T const& default_opt_value) const
{
    return params_detail::converter<T>::extract(*this,key,boost::optional<T>(default_opt_value));
}

#define compile_params_get(T) template boost::optional<T> parameters::get(std::string const& key) const; template boost::optional<T> parameters::get(std::string const& key, T const& default_opt_value) const

compile_params_get(std::string);
compile_params_get(value_double);
compile_params_get(int);
#ifdef BIGINT
compile_params_get(value_integer);
#endif
compile_params_get(mapnik::boolean);

}